Question: Which isotope of lead has the least mass excess which decays to thallium-185?
Paraphrase: Which lead isotope has the least excess mass declining to thallium-185?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q1372384 . ?ent wdt:P2160 ?obj . ?ent wdt:P816 wd:Q18883276} ORDER BY ASC(?obj)LIMIT 5 
Answer: lead-185